FFmpeg Scale Multiple of 2: A Guide to Resizing Videos

FFmpeg is a powerful tool for manipulating video files, and one of its most useful features is its ability to resize videos. In this guide, we'll explore how to use FFmpeg's scaling feature to create resized videos with even pixel counts.

To start, let's consider the importance of even pixel counts in video file formats. Some formats require that the width and height of a video be multiples of 2, while others may not support odd-numbered pixels at all. In these cases, it's essential to ensure that your video is resized to a multiple of 2.

One way to achieve this is by using FFmpeg's `scale` filter. This filter allows you to resize a video to a specific height or width, while preserving the aspect ratio. To use it, simply specify the desired height and width as arguments, like so:

ffmpeg -i input.mp4 -vf scale=-2:360 output_360p.mp4

In this example, the `scale` filter is used to resize the input video to 360 pixels tall (or wide, since FFmpeg preserves the aspect ratio), with a multiple of 2. The `-2` flag tells FFmpeg to scale the video to an even number of pixels.

But what if you want to create videos at different resolutions? No problem! You can use the `split` filter to split the input stream into multiple streams, each with its own resolution. For example:

ffmpeg -i input.mp4 -vf split=2 output_360p.mp4,output_720p.mp4

In this case, the `split` filter is used to divide the input video into two separate streams: one at 360 pixels tall and another at 720 pixels tall.

Once you've created your resized videos, you can use FFmpeg's `map` filter to select which stream to use as output. For example:

ffmpeg -i output.mp4 -map 0:v -c:v libx264 output_360p.mp4

In this case, the `map` filter is used to select the first video stream (designated by the `0:v` argument) and encode it using the H.264 codec.

By combining these filters, you can use FFmpeg to create resized videos with even pixel counts, perfect for streaming or publishing on platforms that require specific resolution requirements. With a little creativity and experimentation, you can unlock the full potential of FFmpeg's scaling features and take your video processing to the next level!

Ffmpeg scale multiple of 2